WASHINGTON — The Environmental Protection Agency plans to dissolve its Office of the Science Advisor, a senior post that was created to counsel the E.P.A. administrator on the scientific research underpinning health and environmental regulations, according to a person familiar with the agency’s plans. The person spoke anonymously because the decision had not yet been made public.

Asked about the E.P.A.’s plans, John Konkus, a spokesman for the agency, emailed a prepared statement from the science adviser, Jennifer Orme-Zavaleta, in which she described the decision to dissolve the office as one that would “combine offices with similar functions” and “eliminate redundancies.”

In an email, Dr. Orme-Zavaleta referred questions to the E.P.A.’s public affairs office.

Dr. Orme-Zavaleta is an expert on the risks of chemicals to human health who has worked at the E.P.A. since 1981, according to the agency’s website. It was unclear whether she would remain at the E.P.A. once the decision takes effect.

Separately, on Tuesday, in an unusual move, the E.P.A. placed the head of its Office of Children’s Health, Dr. Ruth Etzel, on administrative leave, while declining to give a reason for the move. Agency officials told Dr. Etzel, a respected pediatric epidemiologist, that the move was not disciplinary. As the head of an office that regularly pushed to tighten regulations on pollution, which can affect children more powerfully than adults, Dr. Etzel had clashed multiple times with Trump administration appointees who sought to loosen pollution rules.

Michael Mikulka, who heads a union representing about 900 E.P.A. employees, said, “Clearly, this is an attempt to silence voices whether it’s in the agency’s Office of Children’s Health or the Office of the Science Advisor to kill career civil servants’ input and scientific perspectives on rule-making.”

The changes at the two offices, which both report directly to the head of the E.P.A., come as the agency’s acting administrator, Andrew Wheeler, a former coal lobbyist, is overseeing a reorganization of the agency.

After dissolving the office of the scientific adviser, Mr. Wheeler plans to merge the position into an office that reports to the E.P.A.’s Deputy Assistant Administrator for Science, a demotion that would put at least two more managerial layers between the E.P.A.’s chief scientist and its top decision maker.

“It’s certainly a pretty big demotion, a pretty big burying of this office,” said Michael Halpern, the deputy director of the Center for Science and Democracy with the Union of Concerned Scientists, an advocacy group. “Everything from research on chemicals and health, to peer-review testing to data analysis would inevitably suffer,” he said.

The move comes after several months in which the leaders of the E.P.A. have systematically changed how the E.P.A. treats science. The agency’s previous administrator, Scott Pruitt, who resigned in July amid allegations of ethical violations, in April proposed a regulation that would limit the types of scientific research that E.P.A. officials could take into account when writing new public health policies, a change that could weaken the agency’s ability to protect public health.

Last year, Mr. Pruitt significantly altered two major scientific panels that advise the E.P.A. on writing public health rules, restricting academic researchers from joining the boards while appointing several scientists who work for industries regulated by the E.P.A.

An earlier version of this article gave an incorrect first name for the deputy director of the Center for Science and Democracy at the Union of Concerned Scientists. He is Michael Halpern, not Mark.

Coral Davenport covers energy and environmental policy, with a focus on climate change, from the Washington bureau. She joined The Times in 2013 and previously worked at Congressional Quarterly, Politico and National Journal. @CoralMDavenport•Facebook

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